GM Service Manual Online
For 1990-2009 cars only

Cleaning Procedure

  1. Clean the exhaust manifold exterior in solvent.
  2. Warning: Refer to Safety Glasses Warning in the Preface section.

  3. Dry the exhaust manifold with compressed air.

Inspection Procedure


    Object Number: 1040942  Size: SH
  1. Inspect the left exhaust manifold for the following:
  2. • Damage to the exhaust manifold-to-cylinder head gasket sealing surface (1)
    • Damage or broken welds (2)
    • Damage to the support bracket (3)
    • Damage to the threads in the exhaust pipe flange (4)
    • Damage to the exhaust pipe flange sealing surface (5)
    • Damage or restrictions within the exhaust passages (6)

    Object Number: 1040955  Size: SH
  3. Inspect the left exhaust manifold for the following:
  4. • Damage to the oxygen sensor threaded hole (1)
    • Damage to the threads for the heat shield mounting (2)
    • Damage or excessive corrosion to the exhaust manifold exterior (3)
    • Damage to the exhaust manifold-to-cylinder head mounting holes (4)
  5. Repair or replace the exhaust manifold and/or components as necessary.

  6. Object Number: 1040971  Size: SH
  7. Measure the alignment or surface flatness of the exhaust manifold flanges, using a straight edge and a feeler gage. Exhaust manifold surface flatness must not exceed 0.254 mm (0.010 in).
  8. If the surface flatness is not within specifications, the exhaust manifold is warped and must be replaced.